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Fengyun Zhao, Junli Sun, Songlin Yu, Huaifeng Liu and Kun Yu

Aeration through subsurface drip irrigation (SDI) can promote plant growth and increase crop yield; however, more research is focused on annual crops, and there are few studies on perennial crops. We have studied a new type of SDI (SDI with tanks) suitable for cultivation and production of perennial fruit trees and photovoltaic aeration device in greenhouse. The results showed that aeration irrigation promoted the growth of new leaves, fine roots, and new branches of grape, regulated O2/CO2 content in rhizosphere soil, and accelerated air exchange in rhizosphere soil. This study showed that aeration irrigation did not change the structure of bacteria and fungi but significantly increased the abundance of aerobic bacteria, such as Nitrospira and Cytophagia. Moreover, it promoted the increase of Pseudomonas and Aspergillus related to phosphate solubilization, that of Bacillus related to potassium solubilization, and that of Fusarium related to organic matter (OM) decomposition. This study shows that aeration irrigation through SDI with tanks can promote grape growth, which may be related to the ability of aeration irrigation to change the gas composition of rhizosphere soil, optimize the structure of rhizosphere soil microorganism.

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Kun Li, Qi-Chang Yang, Yu-Xin Tong and Ruifeng Cheng

In this study, the effects of light-emitting diode (LED) panels with different illumination schedules and mounted above butterhead lettuce (Lactuca sativa var. capitata) seedlings on lettuce growth and photosynthesis were examined, and the performance of the vertical and horizontal movable system on energy savings was evaluated. The illumination schedules used were fixed LED [F-LED (four LED panels illuminated the area below)] and movable LED [M-LED (two LED panels moved left and right once per day to illuminate the same area as F-LED)] at distances of 10 and 30 cm above the seedlings. The plant yields were uniform in all LED treatments. The highest light utilization efficiencies and lowest electricity consumption were found for the treatments with irradiation from a shorter distance above the seedlings. The true leaf numbers and ascorbic acid concentrations were the highest in the M-LED and F-LED treatments at a distance above the seedlings of 10 cm, while the leaf lengths and sucrose concentrations in these groups were significantly lower than those in the 30-cm treatment. These results indicate that illumination with M-LED can halve the initial light source input while maintaining yield and that sustained illumination from a shorter distance above the seedlings is the main factor in electricity savings.